1. Field of the Invention
The invention concerns a tracked transport system, for example a railroad or like system, utilizing one or a plurality of cars on a route in the order of a few hundred meters and in which the one car or each car is driven along a guide track by a cable, a conveyor, conveyor belts or like means; the invention is more particularly concerned with an improvement to a known type of car designed for such utilization and making it possible to achieve reliable emergency braking when necessary.
2. Description of the Prior Art
U.S. Pat. No. 4,512,259 describes a transport system using a car or cars able to accommodate a limited number of passengers (in the order of ten passengers, for example) and designed to convey passengers over average distances in the order of a few hundred meters.
In a system of this kind a cable is driven in a closed loop along the track at all times and the car or cars are temporarily attached to it by appropriate gripping means in order to be drawn from one point to another.
In the abovementioned prior art document the force applied by the gripping means to the cable reflects the load in the car, so that the starting up of its movement is always subjectively experienced in the same way, in particular with the same acceleration, however many passengers may have entered the car. To achieve this, the car or each car is in two parts, respectively a rolling chassis adapted to move along the track and a cabin suspended from the chassis by a set of suspension members attached to a load summing mechanism forming weighing means. This mechanism is also coupled to the cable gripping means so that the gripping force developed by the latter is representative of the load in the cabin, that is to say the number of passengers on board. This arrangement ensures a gradual starting up the car when the gripping means (in the form of braked pulley wheels movable towards each other) close around and grip the cable. When the car arrives at a station the gripping means are released by the action of a cam operating a lever fastened to them and the car is slowed down when one or more braked wheels of the car enter into frictional contact with a succession of decelerator belts running at progressively slower speeds.
According to an advantageous feature of the prior art system, the means for braking the wheels are also coupled to the load summing mechanism forming the weighing means so that the deceleration of the car is substantially independent of the load in the cabin.
This system functions in an entirely satisfactory manner, but if consideration is given to operating it under quasi-automatic conditions, or even without human supervision, a number of safety devices are needed and in particular emergency braking means operated whenever abnormal operation is detected.
The present invention proposes an improvement of this type providing extremely reliable emergency braking, this improvement being advantageously combined with the structure of the car as defined hereinabove and in particular with the aforementioned weighing means.